Slipproof stair unit



June 12, 1923.

1,458,681 A. BONIFACE SLIP PROOF STAIR UNIT Filed March 10, 1919 r a, ,Arn

INVENTOR Patented June 12, 1923.

UNITED STATES ARTHUR BONIFACE, OF NEW YORK, N.

Y., AssIcNon T NORTON comm, or

WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

SLIPIROQF STAIR UNIT.

Application filed March 10, 1919. Serial No. 281,770.

To all whom it may concern:

Be it known that I, ARTHUR BONIFACE, a citizen of the United States of America, residing at New York, in the county of New 6 York and State of New York, have invented certain. new and useful Improvements in Slipproof Stair Units, of which the following is a full, clear, and exact specification.

My invention relates to concrete articles of manufacture and more particularly to the construction of slip-proof stair treads. An efficient and satisfactory stair tread has been found in embedding a tile of ceramic bonded crystalline alumina in the nose of a concrete stair. Considerable difliculty has been experienced in substituting this form of stair tread for the unsafe stairs used, for example, in the approaches to elevated railway structures, since it is not feasible to build a concrete stairway from the plastic material where it is necessary for pedestrians to pass over this surface at fre uent intervals.

It is accordingly an o 'ect of my invention to overcome such diflicuities and to provide as a new article of manufacture a concrete slab havin an anti-slipping nose which is adapted to be quickly laid in place on asuitable stair foundation without seriously impeding pedestrian traffic thereover.

Referring to the drawings, I have there illustrated one embodiment of my invention in which:

Fig. 1 is a plan view; and Fig. 2 is a perspective view of a section of a slab adapted for a stair tread.

My slip-proof stair slab comprises essentially a concrete or cement body having antislipping tiles embedded in one face to form a plane tread surface and having a bottom adapted to be laid on a foundation and suitably fastened thereto.

This slab is an integral and unitary article of rigid and strong construction which may be made up in various shapes and designs at some convenient manufacturing establishment and then shipped to [a desired location where it may be quickly laid in place on a stair foundation without seriously interrupting pedestrian trafiic. This slab may be so constructed that it may be supported and fastened to a stair construction in various ways.

One embodiment of my invention may comprise the construction illustrated in the ca drawings which is adapted to be supported on a flat iron stairway and bolted thereto.

This slab comprises essentially a concretebody 10 having preferably a cement layer 11 thereover, which is adapted to hold the anti-slipping tiles in place and to form a smooth tread portion for the rear of the slab. The slip-proof tiles 12 which I utilize are preferably in the form of flat plates substantially the shape of a parallelepipedon. Having rough porous surfaces, they may be laid in plastic cement and become securely united thereto as the latter hardens. As a further aid to such union and to overcome any tendency to slip forward or move in the cement, the tiles are preferably provided with grooves 13 in their under surfaces.

Since the pedestrian wear on a stairway occurs mainly on its forward edge or adjacent to the nose and not on the rear and end portions thereof, I embed these tiles only in such forward and middle portions, as shown in Fig. 1. The portions in the rear of the tiles and at the ends of the tread are filled with the cement 1 1 to provide a rear surface 14 and sides 15 lane and continuous with the top of the ti es.

In order to add further strength to the concrete slab I may provide suitable reenforcement means such as a wire mesh 16 which is embedded in the concrete. It is within the scope of my invention to providevarious means for fastening this slab to a support. In the embodiment illustrated this may comprise the bolts 17 havin their heads 18 embedded in the concrete an referably above and engaging the wire mes 16.

As a simplified type of process for making this concrete stair slab, I may place the tiles 12 in a suitable mold with their tread portions facing downwardly and the round noses 19 toward one corner of the mold, these blocks having been previously wetted with water and permitted to drain somewhat. A layer 11 of cement mortar of one part of Portland cement to one part of sand mixed with water to the proper consistency is filled in the space in the rear of, and to a level about 1}" above the top of, the tiles and is carefully worked into. grooves 13, between the tiles and around the sides in order to give thorough and intimate contact. After this plastic mass has been put in position and before it can harden I pour in the layer 10, which may comprise a regular concrete mixture of one part are so positioned that their heads'lie below;

the wire mesh in the mold and the stems project outside of the slab. After permitting the cement mixtures to set ,in the mold for a suitable length of time, 'the slab is removed and is then ready for use.

'llhe anti-slipping tiles, which are made 4 by methods not forming a part of my invention, may comprise wear-resisting crystalline grains of alumina, silicon carbide or other materials having a hardness of 9 or more on Mohs scale, which are bonded into a unitary mass by a suitable bond capable of holding these crystalline grains in place almost indefinitely and withstanding the shocks and abrasions of pedestrian footwear. Such a bond referably comprises a ceramic material w ich is made up of suitable clay mixtures such as slip clay mixed with ball clay and felds an in such proportions that when burne at about 1300 0., they produce a very hard bonded and a securing structure. The grain sizes are such as to prevent slipping of footgear but at the same time are small enough so as not to seriously abrade shoe lether. These grains preferably vary in size from a 36 mesh to very fine grains such as will pass a 120 or 180 mesh screen. I Having thus described my invention, what 1' claim as new and desire to secure by Letters Patent is v A unitary, integral stair slab comprising a supporting portion of cement, a row of weapresisting, anti-slipping tiles of 06- ramiE bonded abrasive grains forming the forward part of the tread surface of the slab, said tiles being rough and porous and having plane upper surfaces, rounded abrasive edges forming the nose of the slab and under surfaces integrally adhering to the cement, a portion comprlsing cement in the rear of the tiles having a plane tread level and continuous with the surface of the tiles device embedded in said slab for fastening it to a foundation.

SLifned at New York, N. Y., this 6th day of arch 1919.

ARTHUR BONIFACE. 

